Re: [Qemu-devel] [PATCH] configure: Support system emulation with large memory on w32 hosts

[Stefan Weil <sw@weilnetz.de>]

Am 20.07.2012 05:53, schrieb Alexey Kardashevskiy:
> On 19/07/12 02:37, Stefan Weil wrote:
>> 32-bit applications on Windows normally only get virtual memory in
>> the lower 2 GiB address space.
>>
>> Because of memory fragmentation, VirtualAlloc() usually won't get 1 GiB
>> of contiguous virtual memory in that address space. Therefore running
>> system emulations with 1 GiB or more RAM will abort with a failure.
>>
>> The linker flag --large-address-aware allows addresses in the upper 2 GiB.
>> With this flag, it is possible to run emulated machines with up to
>> 2047 MiB RAM.
>>
>> Signed-off-by: Stefan Weil <sw@weilnetz.de>
>> ---
>>
>> I tested the executables with large address awareness on a 64 bit Windows
>> (works) and with Wine on Debian 32 bit Linux (no longer aborts, but hangs
>> when 1024 or more MiB are requested).
>>
>> Maybe the support for large addresses is broken in my Wine version.
>> Please report any different test results.
>
> I tried with native WindowsXP, the patch did not help.
>
> QEMU was compiled with the new parameter:
>
> Install prefix    c:/Program Files/QEMU
> BIOS directory    c:/Program Files/QEMU
> binary directory  c:/Program Files/QEMU
> library directory c:/Program Files/QEMU/lib
> include directory c:/Program Files/QEMU/include
> config directory  c:/Program Files/QEMU
> Source path       /home/aik/testken/qemu
> C compiler        i686-pc-mingw32-gcc
> Host C compiler   gcc
> CFLAGS            -O2 -D_FORTIFY_SOURCE=2 -g
> QEMU_CFLAGS       -m32 -D__USE_MINGW_ANSI_STDIO=1 -DWIN32_LEAN_AND_MEAN
> -DWINVER=0x501 -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE
> -Wstrict-prototypes -Wredundant-decls -Wall -Wundef -Wwrite-strings
> -Wmissing-prototypes -fno-strict-aliasing  -fstack-protector-all
> -Wendif-labels -Wmissing-include-dirs -Wempty-body -Wnested-externs
> -Wformat-security -Wformat-y2k -Winit-self -Wignored-qualifiers
> -Wold-style-declaration -Wold-style-definition -Wtype-limits
> LDFLAGS           -Wl,--nxcompat -Wl,--no-seh -Wl,--large-address-aware
> -Wl,--dynamicbase -Wl,--warn-common -m32 -static -g
> make              make
> install           install
> python            python
> smbd              /usr/sbin/smbd
> host CPU          i386
> host big endian   no
> target list       ppc64-softmmu
> [...]
>
>
>
> qemu/ppc64-softmmu/qemu-system-ppc64 -M pseries -m 1024 -nographic -L
> qemu/pc-bios/ -net none -append console=hvc0 -initrd ./1.cpio -kernel
> ./guest.vmlinux.n -net nic,model=virtio -net user,hostfwd=tcp::5555-:22
> -drive file=test-virtio-blk.img,if=virtio,index=0,media=disk,cache=unsafe
> ***qemu_memalign 200 (512) size 800 (2048)
> Warning: Disabling some instructions which are not emulated by TCG (0x0, 0x6)
> ***qemu_vmalloc 40000000 (1073741824)
> Failed to allocate memory: 8
>
> This application has requested the Runtime to terminate it in an unusual way.
> Please contact the application's support team for more information.
>
>
> The lines with *** are mine printf("%s %x(%u)", __func__, etc).
>
> It still works with "-m 1023".

Do you have enough RAM? Even with 64 bit Windows 7, I am
limited to -m 7000 with 64 bit QEMU on a 8 GiB host.
32 bit QEMU runs there with up to 2047 MiB.

On 32 bit Windows XP, I'd expect that you need 2 GiB (or better
3 GiB) of physical RAM in your host, and close all other
programs before you try QEMU.

Maybe I can run a test with Windows XP during the weekend.

By the way: the patch must be modified to work for 64 bit QEMU.
MinGW-w64's ld shows the new parameter in its help, but does
not support it for 64 bit executables.

Regards,
Stefan